Photo © James F. Wilson Designing with New provisions and sustainable properties Autoclaved Aerated Concrete by William D. Palmer Jr., PE A utoclaved aerated concrete (AAC) is often called an ‘innovative new building material,’ despite being used in Europe for the past 70 years and in the United States for at least a decade and a half. Although AAC is on the market, gaining acceptance has been slow and painful— as is often the case for new products introduced into the U.S. construction industry. 1 However, autoclaved aerated concrete has two things going for it that could push it more into the mainstream. The first is the design provisions for AAC masonry developed by the Masonry Standards Joint Committee (MSJC), the nationally recognized code-writing group administered by The Masonry Society (TMS), and cosponsored by the American Concrete Institute (ACI) and the Structural Engineering Institute of the American Society of Civil Engineers (SEI/ASCE). Aside from some differences in ‘allowables’ and material properties, the MSJC provisions help ensure engineers familiar with traditional masonry are also able to build using AAC. The second motivating factor that could increase the use of AAC is the current emphasis on sustainable, energy-efficient construction. As described throughout this article, autoclaved aerated concrete’s naturally insulating, fireproof, and sound- resistant characteristics make it a desirable building material for both commercial and residential construction. Solutions for the Construction Industry July 2008
